Refining of mineral oils



Feb. '16, 1943. H, J. MQYE'R 2,311,562

REFINING OF MINERAL OILS Filed April 1, 1941' 2 Sheets-St met 1 cycLo/veSEPARATOR.

CRACKED VAPO2 I I i T CRACKED VAPOR TO 5 I l FRAcTIONA'r/NG COLUMN 4CATALYTIC 72ATION 7 ZOIV 6 SPENT CATALYST I J 0/1. M4202 r20 7-7252HEATER lj Feb. 16, 1943. H, MOYE-R REFINING OF MINERAL OIL Filed April1, 1941 2 Sheets-Sheet 2 Buff Patented Feb. 16, 1943 REFINING OF MINERALOILS Harold J. Moyer, Summit, N. J assignor to Standard Oil DevelopmentCompany, a corporation of Delaware Application April 1, 1941, Serial No.386,253

7 Claims.

The present invention is concerned with the refining of mineral oils.The invention is more particularly concerned with an improved processfor producing a petroleum oil product boiling in the heating oil and gasoil boiling ranges which has a relatively low sulfur concentration.

In accordance with my process, the vapors removed from the catalyticcracking zone are contacted with a hydrocarbon substance, preferablywith a petroleum residuum which is characterized by having the abilityto remove the sulfur compounds therefrom.

It is known in the art to refine petroleum oils by various distillation,cracking, reforming, and related operations. It is also known to producevarious heating oil products by subjecting petroleum oils boiling in thegas oil and reduced crude boiling ranges to temperature and pressureconditions adapted to produce cracking of the same. In these thermalcracking operations the resulting cracked petroleum oil products,particularly the lower boiling oils, contain appreciably less sulfurthan is present in the stock from which they originated. On the otherhand, when feed oils of a similar character are catalytically crackedfor similar boiling range products, the sulphur content of the crackedproducts is not appreciably reduced. I have now discovered a process bywhich catalytically cracked products may be readily reduced in sulfurwhich comprises contacting the same in the vaporous phase with aparticular petroleum oil fraction which preferably comprises arelatively high boiling tar fraction.

My process may be readily understood by reference to the drawingsillustrating embodiments of the same. Figure 1 illustrates amodification of my invention describing the method of contacting, whileFigure 2 illustrates a preferred adaptation in which the heating oilproducts are contacted with a tarry fraction segregated in the reformingof a lower boiling range fraction. Referring specifically to Figure 1,it is assumed for purposes of description that the feed oil comprises apetroleum oil boiling in the gas oil boiling range and that the catalystcomprises an acid treated clay. The feed oil is introduced intocatalytic reaction zone I by means of feed line 2 along with catalystwhich is introduced by means of line 3. Temperature and pressureconditions are adjusted in reaction zone I adapted to secure the desiredconversion of the feed oil. The cracked products are withdrawn overheadfrom zone I by means of line 4 and passed into separation zone 5 whereinthe catalyst is separated from the reaction vapors. It is assumed forthe purpose of description that separation zone 5 comprises a cycloneseparator or equivalent means. The spent catalyst is withdrawn fromseparation zone 5 by means of line 6, regenerated and recycled ordisposed of in any manner desirable. The cracked products are withdrawnfrom the separation zone by means of line I and passed into zone 8wherein the cracked products are treated with a relatively high boilinghigh molecular weight hydrocarbon substance which is introduced intozone 8 by means of line 9. It is assumed that the hydrocarbon substancecomprises a petroleum oil tar which is at a suiiiciently hightemperature so that the tar is in the fluid state. The treated crackedproducts substantial-- ly free of sulfur are removed overhead fromtreating zone 8 by means of line Ill and further refined as desired. Thetar fraction is withdrawn from treating zone 8 by means of line II and.also handled as desired. This fraction is usually cooled and utilized asa heavy fuel oil.

A preferred adaptation of my invention which comprises removing sulfurfrom a heating oil product by treating the same with a tar productsegregated from a low boiling fraction is illustrated in Figure 2. Forthe purpose of description, it is assumed that the feed oil comprises acrude oil. The feed oil is introduced into distillation zone 20 by meansof feed line 2|. Temperature and pressure conditions are adjusted indistillation zone 20 to segregate a fixed gas stream which is removedoverhead by means of line 22, a light naphtha stream which is removed bymeans of line 23, a heavy naphtha stream which is removed by meansofline 24, a gas oil stream which is removed by means of line 25, 'and acrude bottom stream which is removed by means of line 46. It is assumedthat the heavy naphtha stream boils in the range from about 250 F. to425 F., and the gas oil stream boils in the range from about 400 F. toabout 700 F. It is to be understood that distillation zone 20 maycomprise any suitable number and arrangement of distillation units andthat the number of streams segregated in said zone may vary with respectto boiling range and character. In accordance with my process, the heavynaphtha stream removed by means of line 24 is subjected to elevatedtemperature and pressure conditions in reforming zone 26 to producerelatively lower boiling hydrocarbon constituents which are removed bymeans of lin 21 and a relatively high boiling tar fraction which isremoved by means of line 28. Fixed gases and other boiling range streamsare removed from zone 26 and handled in any desirable manner. Thesegregated fraction from zone 26 boiling in the gas oil boiling rangeand removed by means of line 25 is passed through heating zone 29wherein the same is vaporized. The vapors MC their mixed with a powderedcatalyst which is introduced by means of line 30 and the ii'llillllligintioducccl into catalytic cracking zone 3| wherein temperature andpressure conditions as well as the time of contact are adjusted toproduce hydrocarbon constituents boiling in the motor fuel boilingrange. The cracked vaporv ous product containing suspended catalysts isremoved overhead from cracking zone 3! by means of line 32 andintroduced into separation zone 33 wherein the catalyst is separatedfrom the vapors and removed by means of line 34. The cracked vapors freeof catalysts are removed from separation zone 33 by means of line andpassed into contacting zone 36 in which zone the vapors are treatedpreferably countercurrently with at least a port-ion of the tar fractionremoved from reforming zone 26 by means of line 28. The tar fraction isintroduced into the upper part or treating zone 36 by means of line- 31.Temperature and pressure conditions are adjusted s Lila). substantiallyno condensation of the vapors introduced into zone 36 by means oi line35 occurs. sulfur compounds have been separated are-removed overheadirom zone 36 by means-oi line 38 and further handled and refined asdesired.

The treating reagent comprising the tar is with-- means of line 39 maybe desirable to pass the crude bottoms removed by means of line 46through thermal cracking zone 4| and to segregate a petroleum fractionboiling in the motor fuel boiling range on which. is removed from zone Hby means 4 \ltll' ll it is orelw'reu to utilize only re in use 36...ander certain conditions it may Hi: desirable to employ at least aportion of the tar from thermal cracking zone II, in which case the taris passed to zone 36 by means of line 44.

The process of my invention may be widely varied. It is to be understoodthat the process may be adapted in th treatment of cracked productsprodwred in. any catalytic cracking operation utilizing an, Jcccl stuckor m1; catalyst. However, the process is particularly adapted for thetreatment oi products boiling in the motor fuel and heating oil boilingranges: derived from feed oi in the gas o." reduced crude boilingranges, which products are secured by crackl said. iced o ls in the ofcatslyst, as for example, a natural or acid treated clay, svntheticclays, and the like. The heating oil fractions have gravities in thegenera] 1 from about 22 .l. I. to about 32 A. P. 1., preferablygravities in the range from about 25 A. P. l, to 28 A. P. I. The heatingoil lractimis oczl ill '1 "c from about 300 F. to 650 .ytic crackingoperations. 11:11: comp-Ace treat-c i. 315. The operating conditionswill vary considerably depending upon the particular feed oil beingcatalytically cracked and upon the particular catalyst employed. However, in general, the cataiytic cracking operation is cclldoctctl .r;bifilliflhscitixlc'ii it; aiic' from l he treated vapors from which theIt may not be de' by means oi line $2 and also to segregate a tarfractions are reformed at temperaturesapprecb- 700 F. to 1200 F.,preferably at temperatures in the range from about 800 F. to 1000 I".and at pressures in the range from about atmospheric to about 50 poundsper square inch.

The cracked vapors produced by the abovedescribed catalytic crackingoperation are contacted with relatively high boiling hydrocarbonsubstances under conditions which are adapted so that substantially nocondensation of the cracked vapors occurs. In general, I have found thatit is preferred to contact the cracked vapor; at a temperature in therange from about 600 F. to 850 F. preferably in the range from about 750F. to 800 F.

The hydrocarbon substance preferably comprises a petroleum residuum, uchas a petroleum tar. In general, it is preferred that the tar fractionhave a gravity in the range from about 10 A; P. I. to +15 A. P. 1.Although the t8! fraction-may have a sulfur content in the rangefrom-about 4% to 5%, it is preferred that the sulfur content of the samebe in the range below about 1%, preferably in the range below about0.5%. For this reason, a tar fraction segregated from a relatively lowboiling oil, such as a heavy naphtha cut boiling in the genera-l rangefromabout 225 F. to 425 F., is particularlyde'sirable. I have found thata highly cracked'ta'r whfch'bas been produced in a cracking operation inwhich relatively high temperatures are employed is do sirable. inga'tarfraction segregated in the reforming of a heavy naphtha fraction.since 'heavy naphthaably higher than those employed in the cracking ofrelatively higher boiling fractlt'ms, such-"as gasoil fractions andreduced crude fractions."

The activity of the tar with respect to its ability for the removal ofsulfur decreases with time;

It is therefore desirable in the removal of sulfur be construed aslimiting thesame in any manner whatsoever.

Example 1 3 A West Texas petroleumoil fraction boiling in the gas oilboiling range which had a sulfur-concentration of 1.88% was crackedat a;temperature of about 950 F. at a pressure of about 750 pounds per squareinch. No catalyst was employed. The sulfur concentration in therespective segregated cracked fractions was as follows:

Per cent sulfur In another operation, a West Texas reduced crude havinga sulfur concentration of 3.12% was cracked at a temperature of 910 F.and at a pressure or 758 pounds per square inch. The

This increases the desirability of utilizsulfur concentration in therespective cracked fractions was as follows:

Per cent sulfur West Texas gas oil 3.12 Motor fuel-400 F. end point 0.8Heating oil 1.5 Gravity, A. P. I 325 Initial boiling point 214 F. 10%distilled at 408 F. 50% distilled at 474 F. 90% distilled at 575 F.Final boiling point 622 F. Heavy cycle gas oil 2.7 Tar (10 A. P. I.) 3.5

West Texas gas oil 1.88 Motor fue1400 F. end point .165 Heating oil 1.87

Gravity, A. P. I 235 Initial boiling point 242 F.

10% distilled at 438 F.

50% distilled at 460 F.

90% distilled at 540 F.

Final boiling point 627 F. Heavy cycle gas oil 2.12

From the above it is apparent that in a catalytic cracking operation thesulfur concentration in the heating oil is practically identical withthe sulfur concentration in the feed oil to the cracking zone.

Example 4 In an operation conducted identical to that described withrespect to Example 3, except that the cracked products were contactedwith a tar segregated from a heavy naphtha reforming operation, theresults are as follows:

Per cent sulfur West Texas gas oil 1.88 Motor fuell00 F. end point .153Heating oil .95 Gravity, A. P. I 23.5" Initial boiling point 242 F. 10%distilled at 438F. 50% distilled at 460 F. 90% distilled at 540 F. Finalboiling point 527 Heavy cycle gas oil 1.60

Thus, it is apparent that the process of the present inventionmaterially aids in the removal of sulfur from heating oil fractions.

What I claim as new and Wish to protect by Letters Patent is:

1. Process for removal of sulfur compounds from hydrocarbon vaporsproduced in catalytic cracking operations which comprises contactingsaid hydrocarbon vapors with a relatively high boiling liquidhydrocarbon having a gravity in the range from about -5 A. P. I. toabout +10 A. P. I. at a temperature in the range from about 600 F. to850 F.

2. Process for the production of a relatively low sulfur heating oilfraction, which comprises catalytically cracking a feed oil, separatinghydrocarbon vapors comprising constituents boiling in the heating oilboiling range, contacting the hydrocarbon vapors with a petroleum oiltar under conditions so that substantially no condensation of thehydrocarbon vapors occurs, separating the hydrocarbon vapors andsegregating the heating oil therefrom.

3. Process as defined by claim 2, in which said tar comprises a crackedtar and is characterized by having a gravity in the range from about -5A. P. I. to about +l0 A. P. I.

A. Process as defined in claim 2, in which said feed oil comprises apetroleum oil fraction boiling in the gas oil boiling range and in whichsaid petroleum oil tar is segregated from a heavy naphtha reformingoperation.

5. Process for the segregation of a cracked low sulfur heating oilfraction from a petroleum crude oil, which comprises segregating apetroleum crude oil into fractions comprising a heavy naphtha fractionand into a gas oil fraction, reforming said heavy naphtha fraction andsegregating tar therefrom, catalytically cracking said gas oil fractionunder conditions to produce vapors comprising heating oil constituents,countercurrently contacting said vapors with said tar, separating thevapors and recovering a low sulfur heating oil therefrom.

6. Process as defined by claim 5, in which said heavy naphtha fractionboils in the range from about 250 F. to 425 F., and in which said gasoil fraction boils in the range from about 400 F. to 700 F.

7. Process as defined by claim 5, in which said heavy naphtha fractionboils in the range from about 250 F. to 425 F., said gas oil fractionboils in the range from about 400 F. to 700 F.. and in which said tarhas a gravity in the range from about 5 A. P. I. to about +10 A. P. I.

HAROLD J. MOYER.

